Hydrogen production by reaction of carbon with steam and oxygen

ABSTRACT

A process for producing a hydrogen-rich gas mixture which is lean in CO and CH4 relative to CO2 which comprises: A. CONTACTING SUBDIVIDED CARBONACEOUS MATTER WITH STEAM AND OXYGEN IN A REACTION ZONE AT TEMPERATURES BETWEEN ABOUT 800* F. and 1,350* F. to form H2 and CO2, b. maintaining the temperatures in the reaction zone within 100* F. of the average temperature for the reaction zone, C. WITHDRAWING THE HYDROGEN-RICH GAS MIXTURE FROM THE REACTION ZONE, AND D. FEEDING SUFFICIENT STEAM TO THE REACTION ZONE SO THAT THE HYDROGEN-RICH GAS MIXTURE WHICH IS WITHDRAWN FROM THE REACTION ZONE CONTAINS AT LEAST 60 VOLUME PERCENT STEAM.

Iiited States Patent [72] Inventors Melvin M. liIoIm 1,926,587 Alameda;2,436,938 Paul E. Fischer, Laiayette, both of Calif. 3, 04,339 [21]App]. No. 830,468 3,188,179 [22] Filed June 4, 1969 [45] Patented Oct.26, 1971 [73] Assignee Chevron Research Company San Francisco, Calif. DeJonghe [54] HYDROGEN PRODUCTION BY REACTION OF CARBON WITH STEAM ANDOXYGEN com rises. 6 Claims, 1 Drawing Fig. p

[ 2] 11.8. C1 48/206, 23/19 V, 23/140, 23/183, 23/212, 48/202, 48/204[51] Int. Cl Cj 3/16 [50] Field of Search 48/204, 206, 202, 197;252/373; 23/212, 212 A, 212 B [5 6] References Cited UNITED STATESPATENTS 1,505,065 8/1924 West et a1. 48/204 COKE 9/1933 Hansgvig 3/1948Scharmann et a1.

Tornquist 6/1965 Gorin Primary Examiner-Joseph Scovronek Att0rneysA, L.Snow, F. E. Johnston, C. J. Tonkin and T. G.

AiBSTRACT: A process for producing a hydrogen-rich gas mixture which islean in CO and CH, relative to CO which a. contacting subdividedcarbonaceous matter with steam and oxygen in a reaction zone attemperatures between about 800 F. and 1,350 F. to form H and CO b,maintaining the temperatures in the reaction zone within 100 F. of theaverage temperature for the reaction zone,

reaction zone, and d. feeding sufficient steam to the reaction zone sothat the hydrogen-rich gas mixture which is withdrawn from the reactionzone contains at least 60 volume percent steam.

2 KzCOa PULVERIZING MAKEUP ZONE 7- z RECOVERED KZCOJ 7\ V 72 7 Ir 9 4 xco coxs o, A WATER CONTACTOR SOLUTION MAKEUP WATER REMOVAL Hz+COz +$TEAMM 76 W REACTION M 02 L ZONE 22 FLUE GASES STEAM 24 19 STEAM w TGENERATION'B' A-LRB- 7 ZONE 2 RECOVERED KzCO; AND K c0 J METALS 2 3RECOVERY RECOVERED 25 METALS c. withdrawing the hydrogen-rich gasmixture from the PATENTEUU'U 2s 19?! 2 K2CO3 \PULVERIZING MAKEUP ZONE 6$7 RECOVERED ao V 72 17 9 "zcos'coKE KaCO CONTACTOR SOLUTION MAKEUP 1oWATER ,8

REMOVAL H2+CO2+STEAM REACTION O2 ZONE .22 FLUE GASES 2o I9 STEAM WATER\GENERATION1 7 ZONE 2, REcovERE0 a a AND K CO METALS a 3 RECOVERYRECOVERED 25 METALS K 28 .26

UNVENTORS MELVIN M. HOLM PAUL E. FISCHER BY VJ lyh L 01%;

AVTQRNEYS HYDROGEN PRODUCTION BY REACTION OF CARBON WllTl-ll STEAM ANlDOXYGEN BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to the production of a hydrogen-rich gas; moreparticularly, the present invention relates to the production of an H-CO gas mixture in a process wherein steam and oxygen are reacted withcarbonaceous matter. Our application Ser. No. 830,469 titled HydrogenProduction by Reaction of Carbon with Steam, filed on June 4, 1969,relates to a hydrogen production process somewhat similar to the processof the present patent application, and the disclosure of the aforesaidpatent application is hereby incorporated by reference to the presentpatent application.

2. Description of the Prior Art Various methods have been suggested forthe production of hydrogemrich gas mixtures. Among these methods aresteamhydrocarbon reforming, partial oxidation of hydrocarbons, Lurgiheavy hydrocarbon gasification, the traditional steam, red-hot cokereaction, and modified methods of reacting carbonaceous matter withsteam and oxygen, such as described in US. Pat. No. 1,505,065.

The two leading processes, that is the two processes which are mostfrequently used to generate hydrogen, are steamH- hydrocarbon reformingand partial oxidation of hydrocarbons.

in typical steam reforming processes, hydrocarbon feed is pretreated toremove sulfur compounds which are poisons to the reforming catalyst. Thedesulfurized feed is mixed with steam and then is passed through tubescontaining a nickel catalyst. While passing through the catalyst-filledtubes most of the hydrocarbons react with steam to form hydrogen andcarbon oxides. The tubes containing the catalyst are located in areforming furnace, which furnace heats the reactants in the tubes totemperatures of l,2001,700 F. Pressures maintained in the reformingfurnace tubes range from atmospheric to 450 p.s.i.g. If a secondaryreforming furnace or reactor is employed, pressures used for reformingmay be as high as 450 p.s.i.g. to 700 p.s.i.g. in secondary reformerreactors, part of the hydrocarbons in the effluent from the primaryreformer is burned with oxygen. Because of the added expense, secondaryreformers are generally not used in hydrogen manufacture but are usedwhere it is desirable to obtain a mixture of H and N as in ammoniamanufacture. The basic reactions in the steam reforming process are:

CH +2 02CO +4H Because the hydrogen product is used in high-pressureprocesses, it is advantageous to operate at high pressure to avoid highcompression requirements. However, high pressures are adverse to theequilibrium; and higher temperatures must be employed. Consistent withhydrogen purity requirements of about 95 to 97 volume percent H in thefinal H product, and consistent with present metallurgical limitations,generally single stage reforming is limited commercially to about 1,550F. and 300 p.s.i.g.

In typical partial oxidation processes, a hydrocarbon is reacted withoxygen to yield hydrogen and CO. lnsufficient oxygen for completecombustion is used. The reaction may be carried out with gaseoushydrocarbons or liquid or solid hydrocarbons, for example, with methane,the reaction is:

CH +l/20 .Z2H +CO With heavier hydrocarbons, the reaction may berepresented as follows:

Both catalytic and noncatalytic partial oxidation processes are in use.Suitable operating conditions include temperatures from 2,000 F. up toabout 3,200 F. and pressures up to about 1,200 p.s.i.g., but generallypressures between and 600 p.s.i.g. are used. Various specific partialoxidation processes are commercialy available, such as the ShellGasification Process, Fauser-Montecatini Process, and the Texaco PartialOxidation Process.

There is substantial CO in the hydrogen-rich gas generated by eitherreforming or partial oxidation, To convert the CO to H and CO one ormore C0 shift conversion stages are typically employed. The CO shiftconversion reaction is:

This reaction is typically effected by passing the CO and H 0 over acatalyst such as iron oxide activated with chromi- Typical analyses forhydrogen-rich gas mixtures produced by steam reforming, partialoxidation and the other hydrogen production processes previouslyreferred to are given in table 1, page 5.

In all processes represented in table 1 it can be seen that considerableCO is produced relative to CO It can be seen from table 1 that none ofthe processes has a ratio of C0, to CO greater than 2 in the rawhydrogen-rich gas mixture produced. The CO which is present in the rawhydrogen-rich gas typically is shift converted to obtain additional Hand C0 as mentioned previously in the discussion of the steam reformingand partial oxidation processes. CO is more easily removed from hydrogenthan is CO. Also, it can be readily seen from the reactions C-l-H 0*CO+Hthat more hydrogen is produced when carbon is oxidized fully to obtainCO rather than partially to obtain CO. Similarly, more hydrogen isproduced when hydrocarbons are oxidized completely to form CO and Hrather than partially to form CO and H As indicated by table 1, US. Pat.No. 1,505,065 relates to a process wherein steam and oxygen are reactedin a reaction apparatus with carbonaceous matter to obtain ahydrogen-rich gas mixture. It is stated in that patent that a lowtemperature favors the production of carbon dioxide, but yet that thetemperature must be sufficiently high to enable the reaction to proceedat the desired rate. The hydrogen-rich gas mixture which is obtainedaccording to the processes disclosed in U.S. Pat. No. 1,505,065 has a C0to CO ratio of 1.5.

US. Pat. No. 1,505,065 also states that the production of carbon dioxideat a given temperature, pursuant to the reactlon CO+H 0 H +CO is favoredby the presence of an excess of steam above the TABLE 1.HYDROGENPRODUCTION PROCESSES Steam- Lurgi heavy hydrocarbon Partial hydrocarbonSteam, US. Pat.

reforming oxidation gusilication rod-hot coke 1,505,065

H volume percent 74. 2 44. 5 3! 4 50 47 C 0, volume percent 11. 5 40 16.4 4U 12 C 0 volume percent 11.7 5. 3 32. 3 1 18 N2. volume percent 0.30. 4 0. 4 23 CH4, volume percent 2. 2 0.6 11. 3 Volume ratio, number 00/00. 1 0. 1 2 0. 02 1. 5 Volume ratio, number Cog/C114. 5. 3 t) 2. ti Odant Steam Steam Hydrogen gas withdrawal temperature, F 1, 525 2, 700 i,800 2, 730-3, 270 1, 112-1, 382

l Steam plus 0 2 Steam plus air.

amount of steam which actually reacts with the carbonaceous matter. Theamount of steam used according to the process disclosed in U.S. Pat. No.1,505,065 is about 3 to 5 pounds per pound of carbon gasified. On anitrogen-free basis, the upper limit (5 pounds per pound of carbongasified) of the amount of steam 'used according to the disclosure ofU.S. Pat. No. 1,505,065 would result in about 42 volume percent steam inthe hydrogen-rich gas which is produced. Using 23 volume percentnitrogen as the nitrogen content of the hydrogen-rich gas producedaccording to the process of U.S. Pat. No. 1,505,065, the percent steamin the hydrogenrich gas produced is about 33 volume percent.

U.S. Pat. No. 1,505,065d6es not disclose the use of excess steam tominimize the methane content of the hydrogen-rich gas mixture which isproduced.

SUMMARY OF THE INVENTION According to the invention, a process isprovided for producing a hydrogen-rich mixture which is lean in CO andCH, relative to CO which comprises:

a. contacting subdivided carbonaceous matter with steam and oxygen in areaction zone at temperatures between about 800 F. and 1,350 F. to formH and CO b. maintaining the temperatures in the reaction zone within 100F. of an average temperature for the reaction zone,

c. withdrawing the hydrogen-rich gas mixture from the reaction zone, and

d. feeding sufiicient steam to the reaction zone so that thehydrogen-rich gas mixture which is withdrawn from the reaction zonecontains at least 60 volume percent steam.

The present invention is based partly upon the finding and determinationthat a hydrogen-rich gas which is relatively lean in methane, and alsorelatively lean in carbon monoxide, can be produced if carbon is reactedwith steam at a relatively low and substantially uniform temperature anda sufficient amount of steam is fed into the reaction zone, so that thehydrogenrich gas mixture which is withdrawn from the reaction zonecontains at least X60 volume percent steam. Preferably the substantiallyuniform temperatures are maintained in the reaction zone by distributingthe oxygen throughout the reaction zone, so that temperature gradientsin the reaction zone are minimized. Usually the temperatures aremaintained within plus or minus 100 F. of the arithmetic averagetemperature for the reaction zone. The arithmetic average temperaturefor the reaction zone is determined, for example, by taking fivetemperature readings at evenly spaced positions along the vertical axislength of the zone, or reactor, where the carbonsteam reaction is takingplace.

Because the reaction is an endothermic reaction, heat is required tomaintain the elevated temperature in the reaction zone. According to theprocesses in the present invention, this heat is supplied, at least inpart, by the reaction of oxygen with carbonaceous matter in the reactionzone.

The primary reaction in the reaction zone is the generation of hydrogenaccording to the endothermic reaction:

The primary reaction to generate the necessary heat for the aboveendothermic reaction is C+O 'CO However, if the hydrocarbons are presentin the carbonaceous matter fed to the reaction zone, as is usually thecase, then the reaction of the oxygen to generate heat will also resultin the generation of H 0, as for example, according to the reaction Thusin the processes of the present invention, the oxygen which is fed tothe reaction zone supplies not only heat for reaction of oxygen thecarbon-steam reaction but also supplies hot steam when hydrocarbons arepresent in the carbonaceous feed to the-reaction zone.

The present invention differs from our application Ser. No. 850,469titled HYDROGEN PRODUCTION BY REAC- TION OF CARBON WITH STEAM," filed onJune 4, 1969,

inasmuch as in that application steam is contemplated as the heat sourcefor the endothermic carbon-steam reaction,

whereas in the present application oxygen is required to burn at least aportion of the carbonaceous matter in the reaction zone to provide theheat for the carbon steam reaction. Also, according to the presentinvention, temperatures in the reaction zone are maintained within arelatively narrow range. The relatively narrow and substantially uniformtemperatures maintained in the reaction zone according to the process ofthe present invention result in low CO production relative to COAccording to the process of the present invention, a sufficiently largequantity of steam is fed to the reaction zone so that the hydrogen-richgas mixture which is withdrawn from the reaction zone contains at least60 volume percent steam. The large excess of steam, coupled with therelatively low temperatures maintained in the reaction zone, results inthe production of a hydrogen-rich gas mixture which is lean in CH,, aswell as CO, relative to CO In the process of the present invention it ispreferred to contact the subdivided carbonaceous matter with steam andoxygen in the reaction zone at temperatures below l,350 F., as, forexample, at temperatures between about 800 and l,l00 F. However at theselow temperatures the reaction rate of carbon with steam to form hydrogenis slow relative to higher temperatures, as, for example, 1,500 F.typically used in steam-methane reforming or 2,700 F. typically used inpartial oxidation process or about 3,000 F. typically used in hydrogenproduction by steam-coke reactions. Contrariwise, according to apreferred embodiment of the present invention, relatively lowtemperatures (800 to l,l00 F.) are employed and a satisfactory quantityof hydrogen is produced per unit time for commercial purposes by using alarge mass of carbonaceous matter in the reaction zone. Thus, in thispreferred embodiment of the present invention, it is preferred tomaintain the temperature in the reaction zone between about l,000 F. andl,l00 F., and to use about l5,000 cubic feet of subdivided carbonaceousmatter so that at least 500,000 standard cubic feet per day (SCFD) ofhydrogen are produced. STill more preferably, at least about 300,000cubic feet of carbonaceous matter are maintained in the reaction zone soas to produce 10,000,000 SCFD of hydrogen. The larger hydrogenproduction rate results in an overall more economical hydrogen plant,from the standpoint of both investment and operating cost per unitquantity of hydrogen produced.

In the process of the present invention the temperatures are maintainedsufficiently low in the reaction zone and/or sufficient steam is fed tothe reaction zone so that the hydrogenrich gas mixture which iswithdrawn from the reaction zone is relatively lean in both CH and CO.Preferably, the temperature and steam are adjusted so that the ratio ofCO to CH is at least X2.5 and the ratio of CO to CO is at least 2.5.More preferably, the temperature and steam are adjusted so that theratio of CO to CH is at least X40 and the ratio of CO to CO is at least4.0.

In the process of the present invention wherein carbon is reacted withsteam to form hydrogen, it has been determined that various alkalinecarbonates act as catalysts to speed up the rate of reaction. In apreferred embodiment of the present invention, the carbonaceous matterwhich is contacted with steam and oxygen in the reaction 'zone is aresidue material from a process wherein hydrocarbons are extracted fromcoal, said residue material containing an alkaline material such as KCOX Numerous processes have been proposed for use in the United Statesand one or more processes have been used in Western Germany for theconversion of coal to liquid hydrocarbons. In these processes a residueis obtained which has a low hydrogen content, a relatively high carboncontent, and a substantial metals content. Also, almost all coalscontain an appreciable quantity of alkaline materials which is presentin the residue from coal conversion processes. Among these alkalinematerials K CO is prominent, and K CQ, has been found to be aparticularly good catalyst for the steamhydrocarbon reaction as carriedout in the process of the present invention.

According to the preferred embodiment of the present invention, aresidue from a coal extraction process is used as the carbonaceous feedto the steam-carbon reaction zone, and the hydrogen which is generatedis in turn used within the coal extraction process. The hydrogen is usedin the overall coal extraction process to hydrogenate the coal and coalproducts, in order to obtain from the coal a substantial yield ofvaluable hydrocarbon products from the coal such as gasoline and fueloil. This particular preferred embodiment is advantageous not onlybecause the typically 20 percent-by-weight carbonaceous residue from acoal extraction process contains inherent cata' lytic material for thecarbon-steam reaction of the present invention, but, also, because theresidue from the coal extraction process is obtained in a finelysubdivided condition, and, thus, in a reasonably reactive conditionwithout providing further pulverizing; also, because a relatively largeportion of hydrogen, on the order of 5,000 cubic feet per barrel of coalextract, is required to convert the coal extract to marketable liquidfuel products.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic process-flowdiagram of the process of the present invention wherein carbonaceousmatter is reacted with steam and oxygen to provide an H2-CO2 gasmixture.

DETAILED DESCRIPTION OF THE DRAWING Referring now in more detail to thedrawing, coke is introduced via line 1 to pulverizing zone 2. Variousother feeds may be used instead of coke, such as coal or other solidcarbonaceous matter. By carbonaceous matter is meant any substancecontaining carbon, either in the amorphous or crystalline carbon stateand/or as hydrocarbon compounds. Petroleum coke is particularlypreferred feed. The pulverizing zone grinds the solid code to smallparticles, preferably 8 to 42 Tyler mesh size, and more preferably 100to 200 mesh size. The smaller mesh sizes have been found by experimentalwork to result in a considerably faster reaction rate when steam iscontacted with the particles at elevated temperature.

For an example case, about 1,300 tons per day of coke are fed topulverizing zone 2 and about 820 tons per day of coke are passed to liCO coke contacting zone l. In zone 4 the finely subdivided carbonaceousmatter is impregnated with K CO added in aqueous solution form to zone 4via line 12. The aqueous solution of K CO is made up in zone 8. Makeupl( CO via line 5 and recovered I( CO via line 6 are combined andintroduced in zone 0 via line '7. Recycle water via line 110 and watermakeup via line 9 are combined and added to zone 8 via line 11.

The finely divided coke particles which have been impregnated with K COare withdrawn from zone 4i via line 13 in an aqueous slurry form. Wateris separated from the slurry in water-removal zone 14. The water whichis removed is recycled via line to be used again in forming the aqueoussolution of K CO The finely divided coke particies impregnated with KCQ, are withdrawn via line 15 from water-removal zone M substantiallyfree of excess water. The coke particles are fed to reaction zone ll 6,wherein they are reacted with steam introduced to reaction zone 16 vialine 17.

Oxygen is added to reaction zone 16 via line 30. In reaction zone 16 theoxygen reacts with carbonaceous matter to provide heat, for example,according to the reaction The oxygen is distributed in the reaction zoneby means of a mechanical inlet distributor and/or by means of turbulencemaintained within the reaction zone. In the process of the presentinvention, it is preferred to introduce the oxygen to the steam-carbonreaction zone by means of a distributor having multiple oxygen-outletnozzles. In addition, preferably the reaction zone is comprised of afluidized system with upwardflowing vapors and gases, including steam,maintaining the finely divided carbonaceous particles in a fluidized andturbulent state. With the finely divided carbonaceous particles in afluidized state, uniform mixing is more readily achieved in the reactionzone, so that a relatively uniform and relatively low reactiontemperature may be maintained, even though carbon and also hydrocarbonsare being burned in the reaction zone by reaction with oxygen.

The K CO which was previously impregnated into the fine coke particleshas a catalytic effect on the reaction Other alkaline carbonates alsohave been determined to have a catalytic effect on the above reaction.Alkaline carbonates are frequently present in coal and coke and othercarbonaceous matter in appreciable concentrations such as 2-to -5 weightpercent. Thus, in many instances the process of the present inventioncan be carried out catalytically but yet without adding any makeupcatalysts.

The hydrogen-rich stream which is produced in reaction zone 16 iswithdrawn in line 118 from the reaction, together with a large amount ofunreacted steam in accordance with the process of the present invention.

The steam which is fed to reaction zone 16 in large quantities isgenerated in steam generation zone 19. Steam generation zone 19 operatesessentially in accordance with wellknown procedures nonnally used for aboiler plant. Water is added to steam generation zone 19 via line 20 andvaporized to form steam at a temperature of about l,500 F. to l,800 F.The hot steam is withdrawn in line 17.

According to a preferred embodiment of the present inven tion, heatingfuel for the steam generation zone is provided, in part, by using aportion of the coke withdrawn via line 22 from pulverizing zone 2. Insome instances it is economically preferable to omit pulverizing thecoke which is used as a fuel for steam generation zone 19. However, inthe preferred embodiment illustrated by FIG. l, 480 tons per day ofpulverized coke are fed to steam generation zone 19 via lines 3, 22 and21. This 480 tons per day of coke are augmented by 108 tons per day ofunreacted carbonaceous matter (together with metallic ash and K COwithdrawn from reaction zone 16 via line 23.

After burning, the coke and unreacted carbonaceous matter comprised of KCO and metals (or ash) are left. This residue is withdrawn from steamgeneration zone 19 via line 25 and is passed to K CO and metals recoveryzone 26. In zone 26, K CO is separated and withdrawn via line 27, TheKCQ, may then be recycled to zone 8 via line 6.

Metals such as vanadium and nickel are removed in the oxide form fromzone 26 via line 28. The stream of recovered metals may be subjected tofurther processing to obtain satisfactory separation of valuable metals,or metal compounds, from less valuable ash constituents. Becausehydrogen is advantageously produced in the process of the presentinvention from heavyX" carbonaceous matter such as coal, coke orpetroleum residue, the overall process of the present invention affordsan attractive process to recover metals from various carbonaceousmaterials. Metals are recovered both from coke fed to the steamgeneration zone from the pulverizing zone and from unreacted materialwithdrawn via line 23 from reaction zone 16. V

Referring once again to reaction zone 16, example numbers for apreferred embodiment of the present invention include the following: thecoke fed to reaction zone 16 preferably contains about 0.2 pounds of thecatalytic agent K CO per 0.8 pounds of coke. It is preferred to carryout the reaction using a large volume of coke so that large quantitiesof hydrogen-rich gas can be generated at relatively low temperatures.Thus, on a basis of 820 tons per day of K CO free coke, two reactors,each 20 feet in diameter by 64 feet long, are required in this preferredembodiment wherein million SCFD of hydrogen are produced. The reactorsare operated at an Internal pressure of approximately 250 p.s.i.g. Heatrequired per pound of carbon reacted, in accordance with the endothermicsteam-carbon reaction employed in the process of the present invention,is about 3,600 B.t.u.s per pound of carbon reacted. To furnish therequired heat, about 740,000 per pounds per hour of steam are added tothe reactor vessels at a temperature of about 1,680 steam are selectedso that there will be at least 60 volume percent steam in thehydrogen-rich gas withdrawn from the reactors, and so that thetemperature at which the hydrogen-rich gas is withdrawn is between 800F. and l,200 In this particular instance there is about 67 volumepercent steam in the hydrogen-rich gas withdrawn from reaction zone 16,and the temperature of the hydrogen-rich gas which is withdrawn is about1,200 F.

Although various specific embodiments of the invention have beendescribed and shown, it is to be understood they are meant to beillustrative only and not limiting. Certain features may be changedwithout departing from the spirit or essence of the invention. It isapparent that the present invention has broad application to theproduction of hydrogen-carbon dioxide gas mixtures. Accordingly, theinvention is not to be construed as limited to the specific embodimentsillustrated but only as defined in the appended claims.

We claim:

1. A process for producing a hydrogen-rich gas mixture which is lean inCO and CH relative to CO and having a ratio of CO to CH of at least 2.5and a ratio of CO to C of at least 2.5 which comprises:

a. contacting subdivided carbonaceous matter with steam and oxygen in areaction zone at temperatures between about 800 and 1,350X F. to form Hand CO b. maintaining the temperatures in the reaction zone within 100F. of the average temperature for the reaction zone,

c. withdrawing the hydrogen-rich gas mixture from the reaction zone, and

F. The temperature and the amount of 5 d. feeding sufiicient steam tothe reaction zone so that the hydrogen-rich gas mixture which iswithdrawn from the reaction zone contains at least 60 volume percentsteam.

2. A process in accordance with claim 1 wherein sufficient steam is fedto the reaction zone so that the hydrogen-rich gas mixture which iswithdrawn from the reaction zone has a ratio of CO to CH, of at least4.0 and a ratio of CO to C0 of at least 4.0.

3. A process in accordance with claim 1 wherein the subdividedcarbonaceous matter is contacted with steam and oxygen in the reactionzone at temperatures between about 8 00 and 1,100 F.

4. A process in accordance with claim 3 wherein sufficient steam is fedto the reaction zone so that the hydrogen-rich gas mixture which iswithdrawn from the reaction zone has a ratio of CO to CH, of at least4.0 and a ratio of CO; to C0 of at least 4.0.

tion zone, and d. feeding sufficient steam to the reaction zone so thatthe hydrogen-rich gas mixture which is withdrawn from the reaction zonehas a ratio of CO; to CH, of at least 2.5 and a ratio of CO to CO ofatleast 2.5.

6. A process in accordance with claim 5 wherein at least about 300,000cubic feet of subdivided carbonaceous matter is maintained in thereaction zone.

2. A process in accordance with claim 1 wherein sufficient steam is fedto the reaction zone so that the hydrogen-rich gas mixture which iswithdrawn from the reaction zone has a ratio of CO2 to CH4 of at least4.0 and a ratio of CO2 to CO of at least 4.0.
 3. A process in accordancewith claim 1 wherein the subdivided carbonaceous matter is contactedwith steam and oxygen in the reaction zone at temperatures between about800* and 1,100* F.
 4. A process in accordance with claim 3 whereinsufficient steam is fed to the reaction zone so that the hydrogen-richgas mixture which is withdrawn from the reaction zone has a ratio of CO2to CH4 of at least 4.0 and a ratio of CO2 to CO of at least 4.0.
 5. Aprocess for producing a hydrogen-rich gas mixture which is lean in CO2and CH4 relative to CO2 which comprises: a. contacting subdividedcarbonaceous matter with steam and oxygen in a reaction zone attemperatures between 800* and 1, 100* F., b. maintaining thetemperatures in the reaction zone within 100* F. of the averagetemperature for the reaction zone, c. withdrawing the hydrogen-rich gasmixture from the reaction zone, and d. feeding sufficient steam to thereaction zone so that the hydrogen-rich gas mixture which is withdrawnfrom the reaction zone has a ratio of CO2 to CH4 of at least 2.5 and aratio of CO2 to CO of at least 2.5.
 6. A process in accordance withclaim 5 wherein at least about 300,000 cubic feet of subdividedcarbonaceous matter is maintained in the reaction zone.